<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><link rel="stylesheet" type="text/css" href="style.css" /><script type="text/javascript" src="highlight.js"></script></head><body><pre><span class="hs-comment">-----------------------------------------------------------------------------</span><span>
</span><span id="line-2"></span><span class="hs-comment">-- |</span><span>
</span><span id="line-3"></span><span class="hs-comment">-- Module      :  Control.Monad.Trans</span><span>
</span><span id="line-4"></span><span class="hs-comment">-- Copyright   :  (c) Andy Gill 2001,</span><span>
</span><span id="line-5"></span><span class="hs-comment">--                (c) Oregon Graduate Institute of Science and Technology, 2001</span><span>
</span><span id="line-6"></span><span class="hs-comment">-- License     :  BSD-style (see the file LICENSE)</span><span>
</span><span id="line-7"></span><span class="hs-comment">--</span><span>
</span><span id="line-8"></span><span class="hs-comment">-- Maintainer  :  libraries@haskell.org</span><span>
</span><span id="line-9"></span><span class="hs-comment">-- Stability   :  experimental</span><span>
</span><span id="line-10"></span><span class="hs-comment">-- Portability :  portable</span><span>
</span><span id="line-11"></span><span class="hs-comment">--</span><span>
</span><span id="line-12"></span><span class="hs-comment">-- Classes for monad transformers.</span><span>
</span><span id="line-13"></span><span class="hs-comment">--</span><span>
</span><span id="line-14"></span><span class="hs-comment">-- A monad transformer makes new monad out of an existing monad, such</span><span>
</span><span id="line-15"></span><span class="hs-comment">-- that computations of the old monad may be embedded in the new one.</span><span>
</span><span id="line-16"></span><span class="hs-comment">-- To construct a monad with a desired set of features, one typically</span><span>
</span><span id="line-17"></span><span class="hs-comment">-- starts with a base monad, such as @Identity@, @[]@ or 'IO', and</span><span>
</span><span id="line-18"></span><span class="hs-comment">-- applies a sequence of monad transformers.</span><span>
</span><span id="line-19"></span><span class="hs-comment">--</span><span>
</span><span id="line-20"></span><span class="hs-comment">-- Most monad transformer modules include the special case of applying the</span><span>
</span><span id="line-21"></span><span class="hs-comment">-- transformer to @Identity@.  For example, @State s@ is an abbreviation</span><span>
</span><span id="line-22"></span><span class="hs-comment">-- for @StateT s Identity@.</span><span>
</span><span id="line-23"></span><span class="hs-comment">--</span><span>
</span><span id="line-24"></span><span class="hs-comment">-- Each monad transformer also comes with an operation @run@/XXX/ to</span><span>
</span><span id="line-25"></span><span class="hs-comment">-- unwrap the transformer, exposing a computation of the inner monad.</span><span>
</span><span id="line-26"></span><span class="hs-comment">-----------------------------------------------------------------------------</span><span>
</span><span id="line-27"></span><span>
</span><span id="line-28"></span><span class="hs-keyword">module</span><span> </span><span class="hs-identifier">Control.Monad.Trans</span><span> </span><span class="hs-special">(</span><span>
</span><span id="line-29"></span><span>    </span><span class="hs-keyword">module</span><span> </span><span class="annot"><a href="../../transformers/src/Control.Monad.Trans.Class.html#"><span class="hs-identifier">Control.Monad.Trans.Class</span></a></span><span class="hs-special">,</span><span>
</span><span id="line-30"></span><span>    </span><span class="hs-keyword">module</span><span> </span><span class="annot"><a href="../../base/src/Control.Monad.IO.Class.html#"><span class="hs-identifier">Control.Monad.IO.Class</span></a></span><span>
</span><span id="line-31"></span><span>  </span><span class="hs-special">)</span><span> </span><span class="hs-keyword">where</span><span>
</span><span id="line-32"></span><span>
</span><span id="line-33"></span><span class="hs-keyword">import</span><span> </span><span class="annot"><a href="../../base/src/Control.Monad.IO.Class.html#"><span class="hs-identifier">Control.Monad.IO.Class</span></a></span><span>
</span><span id="line-34"></span><span class="hs-keyword">import</span><span> </span><span class="annot"><a href="../../transformers/src/Control.Monad.Trans.Class.html#"><span class="hs-identifier">Control.Monad.Trans.Class</span></a></span><span>
</span><span id="line-35"></span></pre></body></html>